2021 Global Model Runs Discussion (Out thru day 16)

[skyline385]

Never trust a long range GFS run unless it is supported by multiple ensemble members, cause otherwise it's just one possibility out of hundreds...

[aspen]

The wave is slightly further north and better defined on the 06z operational GFS, but it still fails to develop. 00z GEFS ensembles remain quite active; the 06z GEFS hasn’t loaded yet.

[AlphaToOmega]

The 06Z GEFS ensembles still develop a Western Caribbean storm around October 30-31, a storm in the subtropics around October 26, and a Cape Verde storm around October 29-30. The 00Z ECENS ensembles also still develop a Western Caribbean storm and a Cape Verde storm around the same times as the GEFS, but it does not develop a storm in the subtropics.

[Ubuntwo]

The 06Z GEFS ensembles still develop a Western Caribbean storm around October 30-31, a storm in the subtropics around October 26, and a Cape Verde storm around October 29-30. The 00Z ECENS ensembles also still develop a Western Caribbean storm and a Cape Verde storm around the same times as the GEFS, but it does not develop a storm in the subtropics.

Saying ensembles “develop” or not rather defeats the point. They allow for a probabilistic approach which is much more valuable. For example ~50% of 6z GEFS members have Caribbean development compared to ~70% on yesterday’s 12z.

[Category5Kaiju]

What is it with the GFS's 12z runs loving to show nothing as opposed to the 6z, 18z, and 0z runs?

[Ubuntwo]

What is it with the GFS's 12z runs loving to show nothing as opposed to the 6z, 18z, and 0z runs?

Does not gain enough latitude to develop. Which the models agree on for once. South displaced ITCZ means disturbances hardly make it into the Caribbean if at all. Could develop Pacific side too.

[Category5Kaiju]

What is it with the GFS's 12z runs loving to show nothing as opposed to the 6z, 18z, and 0z runs?

Does not gain enough latitude to develop. Which the models agree on for once. South displaced ITCZ means disturbances hardly make it into the Caribbean if at all. Could develop Pacific side too.
https://imgur.com/KEvQcxN

Idk, ridging this year has not seemed to be quite strong, so I am personally skeptical to see that sort of solution pan out that just presses the wave too far to the south and enters the Pacific instead

[Ubuntwo]

Idk, ridging this year has not seemed to be quite strong, so I am personally skeptical to see that sort of solution pan out that just presses the wave too far to the south and enters the Pacific instead

Caribbean ridging has been stout through October. That shift southward in heights is one factor in the end of a season. I believe this also contributes to the strong upper level winds across the Gulf. Here is the Euro height anomalies analysis:


So it will take a properly timed and oriented trough, dipping quite far south, to permit development.

[aspen]

Bruh the CMC and ICON are showing another EPac system. How on Earth is the East Pacific suddenly being favored during a La Niña October when it has struggled all year prior to this? The lack of anything else on the models in the Atlantic just seemingly defies what is expected of a La Niña and a positive MJO phase. It’s like having two July Atlantic hurricanes and zero EPac storms in July during an El Niño.

[Spacecoast]

12z Shear, and RH.... showing (perhaps) not ideal conditions above 20N early Nov? idk

[LarryWx]

1. The 12Z EPS is now back to being boring (which is great as I don't want to see anything like the disasterous Nov of 2020.
2. The HH GEFS has W Car action but it has slipped back in time a few days.
3. thus, the chances of a W Car TC in early Nov have decreased for now imo.

[aspen]

1. The 12Z EPS is now back to being boring (which is great as I don't want to see anything like the disasterous Nov of 2020.
2. The HH GEFS has W Car action but it has slipped back in time a few days.
3. thus, the chances of a W Car TC in early Nov have decreased for now imo.

inb4 this becomes a November EPac major to continue flexing on the Atlantic.

[Category5Kaiju]

1. The 12Z EPS is now back to being boring (which is great as I don't want to see anything like the disasterous Nov of 2020.
2. The HH GEFS has W Car action but it has slipped back in time a few days.
3. thus, the chances of a W Car TC in early Nov have decreased for now imo.

“For now” is the key, of course. CPC Hazards still shows a moderate chance that we see something form there two weeks from now

[Spacecoast]

ECMF ensembles finally showing possible WCAR genesis after many weeks of non activity.
(GEFS ensembles have not, and still do not show genesis on Alan Brammer's site)
Thin black line is median.



NAV showing 31% genesis of lemon in 114 hours, the other operationals don't indicate this yet..

[Category5Kaiju]

Those are some strong GEFS ensembles in the WCAR

[aspen]

FWIW, both of today’s CMC runs show the wave briefly becoming a TC before making landfall in Costa Rica. The 12z GFS spins it up in the EPac instead.

[blp]

The GEFS continues to disagree with the Ops run not showing the EPAC system and actually showing some strong members. The GEPS also is showing development on the W Caribbean side versus the CMC Ops. Lots of disagreement. I don't think the EPAC has the best conditions to pull out another one.

[jconsor]

The GEFS genesis plots on Brammer's site are broken for the time being. You can verify that by noting that the EPac Genesis map is also blank.

ECMF ensembles finally showing possible WCAR genesis after many weeks of non activity.
(GEFS ensembles have not, and still do not show genesis on Alan Brammer's site)
Thin black line is median.
[url]https://i.ibb.co/FX5MRTY/frcsta6.jpg [/url]


NAV showing 31% genesis of lemon in 114 hours, the other operationals don't indicate this yet..
[url]https://i.ibb.co/jHQpMwm/frcsta7.jpg [/url]

[aspen]

The GEFS, CMC, and ICON have some support for two additional TCs this weekend (Oct30-Nov1) — something forming in the SWCar like Otto ‘16, and a very late MDR system. Anything in the MDR will likely be extremely weak and might not even hit TS status, similar to TD15 in 2019.

[Teban54]

The GEFS, CMC, and ICON have some support for two additional TCs this weekend (Oct30-Nov1) — something forming in the SWCar like Otto ‘16, and a very late MDR system. Anything in the MDR will likely be extremely weak and might not even hit TS status, similar to TD15 in 2019.

Throwback to 2018:
 https://twitter.com/philklotzbach/status/1049670529680953344